Water vapor permeability and water vapor resistance are important elements in the evaluation of the thermophysical wearing comfort of a garment. Knowing the characteristics related to water vapor transfer in a textile or another material is also important for many technical applications.
The measurement of different characteristics related to water vapor transfer are carried out using methods requiring extended measuring intervals. For example, in carrying out the methods of the standard procedures ASTM 96-94 and ISO 11 092, measuring intervals of several hours are necessary. The ASTM 96-94 method is based on a measuring procedure whereby the weight loss of a cup filled with water and covered with the test sample is determined. The weight measurements, repeated at given intervals, and the evaluation of the results, are carried out manually. Thus, the ASTM 96-94 method is considered very labor-intensive. Because of these long measuring times of both methods, routine tests are limited. Furthermore, the tests of the two methods can only be run in a laboratory. Therefore, quality control tests cannot be carried out during production. A critical shortcoming of the standard procedures is also that different measurements are determined under different test conditions so that the results are not comparable.